Preliminary report on the application of the coagglutination test for rapid diagnosis of cholera in the upper Solimöes River area in the Brazilian Amazon region.

The conventional diagnosis of cholera depends on complex bacteriological procedures. Coagglutination is a simple, rapid, inexpensive and efficient technique for the presumptive diagnosis of cholera. Of 840 fecal samples from suspected cases of cholera examined at Tabatinga (State of Amazonas, Brazil) 31 (3.6%) were confirmed by culture and 29 of them were also positive by the coagglutination test performed directly on the fecal enrichment broth (alkaline peptone water). About 90% of the positive coagglutination results were obtained after 5-h incubation at 37 degrees C and the sensitivity, specificity and accuracy of the method were 93.5%, 99% and 98.8%, respectively. Relative to the culture results, coagglutination yielded two false-negative and eight false-positive results. The coagglutination test for cholera can provide a rapid and reliable tool for epidemiological studies and for the planning of more effective measures against cholera.